Saturn’s own orbiting winter wonderland Enceladus may be in the midst of a relatively dry spell, according to new measurements of the thickness of its snowdrifts by a team of researchers from across the US.
Calculations based on the size of a series of depressions called tectonic pit chains suggest that the deposits of ice particles falling from polar geysers could be as deep as 700 meters (about 2,300 feet) in some places. which current eruptions cannot explain.
The findings could mean the frozen moon has had far more active moments in its past, according to a new study led by the first author and research physicist Emil Martin from the National Air and Space Museum.
Though only 500 kilometers (just over 300 miles) across, Enceladus is the sparkling jewel in Saturn’s frozen crown. Not only the moon It is covered with a highly reflective layer of ice and is home to a deep, liquid ocean of salty water just begging to be explored for signs of life.
Thanks to a regular tug of war between Saturn and the more distant moon DioneEnceladus’ frozen shell is periodically massaged by tidal forces, to the point where cracks form in the thinner regions of the crust moonthe south pole.
Pressurized liquid water forces its way into these fissures, where it expands and vaporizes, erupting in a near-vacuum in a supersonic storm of flash-frozen particles.
Some of this frozen spray falls into orbit around Saturn and contributes to its glorious rings. Heavier particles fall back onto the moon‘s surface and accumulate into drifts of what planetary scientists classify as a form of regolith.
In 2017US researchers released high-resolution images from the Cassini mission that detailed what they believed to be geological formations, dubbed pit chains, dotting the surface of Enceladus.
On other planetary bodies, including Earth, these crater-like structures can form when surface material suddenly sinks into a cavity, such as lava tubes or karst cave systems.
Planetary scientists ruled out a source of impacts and a range of other geological activity, concluding that the circular and elliptical pits — some up to a kilometer in diameter — formed when fractures in the crust expanded beneath loose regolith drifts and widened.
Conveniently, the width and depth of the pits themselves researchers can say something about the properties and formation of the regolith that crumbles into them, including an approximation of its thickness.
Applied to the craters on Enceladus, the formulas yielded snow depths averaging about 250 meters, with some depths totaling about 700 meters.
Considering the rate at which icy ocean water clouds could provide a reasonable amount of snow, Enceladus could lay down enough snow in the last few billion years moonThe potential existence of would be for the drifts to be as fluffy and porous as possible.
Although this cannot be ruled out entirely, it is more likely that the snow contained a mixture of densities and porosities, leading researchers to believe that the rate of snowfall must have been much greater on occasion in the past.
That means the geysers could have roared at some point, or there were other plumes spewing frozen water vapor throughout Enceladus’ story. If not both.
Knowing how thick and fluffy the moonPollinating snow at critical locations would be crucial for future probe landings on its surface.
Meanwhile, a better understanding of how cryovolcanic activity evolved on Enceladus is giving us new insights into one of the Solar System’s most intriguing bodies.
This study was published in Icarus.
